Crankshaft main journal regrinding process



Jan. 19, 1965 s. GOLTEN 3,165,866

CRANKSHAFT MAIN JOURNAL REGRINDING PROCESS Filed Nov. 16. 1962 United states Patent O 116, A o Sen Pie.

(u. si -2S9) This invention relates to crankshaft main bearing regrinding processes useful especially in large marine engines. The broad object of the invention is to provide an improved process of regrinding damaged main journals without removing the crankshaft from the engine and without laying up the ship for more than a few days. A more specific object is to provide a process of regrinding several damaged main journals at the same time while the crankshaft is being rotatably supported on its other main journals and is being rotated by the turning engine or other outside source of power.

A journal bearing usually contacts only the central portion of the journal, the ends of the bearing being chamfered to provide clearance so that they do not touch narrow ring areas of the journal adjacent to the crankcheeks. The practice of using the undamaged ring areas at the ends of a journal as reference surfaces in regrinding the journal, to insure that the refinished journal will be coaxial with the original journal, is now well known.

An object of the invention is to provide a process of regrinding several main journals at the same time, each with reference to its undamaged narrow ring areas, while the crankshaft is rotatably supported on its other main journals and is being rotated by the turning engine. A second object is to provide a process of regrinding several main journals at the same time, each coaxial with the axis of rotation of the crankshaft while it is rotatably supported on its other main journals and is being rotated by the turning engine. A third object is to provide a process of regrinding all the main journals of a crankshaft in two steps corresponding, respectively, to the aforesaid first and second objects.

These and other objects of the invention will be apparent from the following specification in connection with the drawings in which FIG. 1 is a diagrammatic elevational view of a crankshaft rotatably supported on several of its main journals while other main journals are being reground; FIG. 2 is a diagrammatic elevational view of the crankshaft rotatably supported on the main journals previously reground, its remaining main journals in process of being reground; FIG. 3 is a diagrammatic sectional view taken on the line 33 of FIG. 1; and FIG. 4 is a diagrammatic sectional View taken on the line 4-4 of FIG. 2.

Referring to the drawings, crankcase 5 operably supports crankshaft 7 in crankshaft main bearing 19. Crankshaft 7 has a plurality of main journals 3 and crankpins 9 connected by crankcheeks 6. Each crankshaft main bearing may be chamfered at both ends as shown at 11, FIG. 1, so that while the central portion of journal 8 may become worn or damaged in service, the narrow ring areas adjacent crankcheeks 6 ordinarily remain true and undamaged.

In preparation for regrinding several of the main journals 3, their corresponding bearings 10 are removed leaving crankshaft 7 rotatably supported on other main journals 8 and corresponding bearings 10 as shown in FIG. 1. A known'type of regrinding mechanism including cupwheel 36 (and means for feeding cupwheel 39 into grinding contact with journal 8 and for moving it in a plane parallel to the axis of journal 8 while in operation) is shown diagrammatically as mounted on U-member 2h having a pair of shoes 31 held in operable contact with the undamaged ring areas of main journal 8 by springs 34 and nuts 33 on studs 32 as showniin FIG. 3. After thus removing bearing 10 and mounting a regrinding mechanism with its cupwheel 3% in position relative to each of several journals 3 as shown in FIGS. 1 and 3, process of regrinding these journals consists of rotating crankshaft 7 by the turning engine or other outside source of power while separately driving, feeding, and moving cupwheels 3d of the regrinding mechanisms so as to regrind these several journals 8 at the same time.

Thereupon, new bearings it? may be fitted to reground journals 8 and crankshaft 7 may be rotatably supported thereon, and the other bearings 10 may be removed while the grinding mechanisms with their cupwheels 30 may be positioned relative to each of the other journals 8 as shown in FIGS. 2 and 4; then the process of regrinding these journals consists of rotating crankshaft 7 by the turning engine while separately driving, feeding, and

moving cupwheels 30 of the regrinding mechanism in a well-known manner so as to regrind these remaining journals S to the same time.

Having thus describedthe invention, it is obvious that the objects, as stated, have been attained in a practical manner. While specific processes have been shown and described, it is obvious that changes may be made therein without departing from the spirit or scope of the invention as expressed in the following claims:

I claim:

1. In a reconditioning engine having a crankshaft with more than three main journals supported in main bearings, the surfaces of said journals (except for narrow ring areas at the ends thereof) having been damaged, the process of regrinding several selected main journals at the same time and without removing the crankshaft from the engine, which process consists of removing the main bearings from the selected main journals leaving the crankshaft operably supported on the other main journals and 7 their bearings, of operable mounting grinding mechanisms on said narrow ring areas of said selected main journals, and of rotating said crankshaft while operating said regrinding mechanisms thereby regrinding said selected main journals coaxially with their respective narrow ring areas.

2. In reconditioning an engine having a crankshaft with more than three main journals supported in main bearings, the surfaces of said journals (except for narrow ring areas at the ends thereof) having been damaged in service: the two-step process of regrinding all of said main journals which consists, first, of rotating the crankshaft supported on a plurality of said damage main journals while regrinding the other main journals coaxially with their narrow ring areas; and, second, of rotating the crankshaft supported on the reground main journals and their bearings while regrinding the remaining damaged journals coaxially with the axis of the crankshaft.

3. In reconditioning an engine having a crankshaft with more than three main journals supported in main bearings, the surfaces of said journals (except for narrow ring areas at the ends thereof) having been damaged in service: the two-step process of regrinding all of said main journals which consists, first, of rotating the crankshaft supported on some of said damaged main journals while regrinding the other main journals coaxially with their narrow ring areas; and, second, of rotating the crankshaft supported on the reground main journals and their bearings while regrinding the remaining damage journals coaxially with their undamaged narrow ring areas.

References Cited in the file of this patent UNITED STATES PATENTS 2,937,479 Golten May 24, 1960 

3. IN RECONDITIONING AN ENGINE HAVING A CRANKSHAFT WITH MORE THAN THREE MAIN JOURNALS SUPPORTED IN MAIN BEARINGS, THE SURFACES OF SAID JOURNALS (EXCEPT FOR NARROW RING AREAS AT THE ENDS THEREOF) HAVING BEEN DAMAGED IN SERVICE: THE TWO-STEP PROCESS OF REGRINDING ALL OF SAID MAIN JOURNALS WHICH CONSISTS, FIRST, OF ROTATING THE CRANKSHAFT SUPPORTED ON SOME OF SAID DAMAGED MAIN JOURNALS WHILE REGRINDING THE OTHER MAIN JOURNALS COAXIALLY WITH THEIR NARROW RING AREAS; AND, SECOND, OF ROTATING THE CRANKSHAFT SUPPORTED ON THE REGROUND MAIN JOURNALS AND THEIR BEARINGS WHILE GRINDING THE REMAINING DAMAGE JOURNALS COAXIALLY WITH THEIR UNDAMAGED NARROW RING AREAS. 